Difference between revisions of "2017-09-18"

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(Created page with " ---- '''LERF (S. Benson)''' September 5-15 *Prepared talks for JPos17, COOL17, and EIC collaboration meeting *Attended JPos17 and organized LERF tour *Continued t...")
 
 
(8 intermediate revisions by the same user not shown)
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 +
'''Director (M. Spata)'''<br>
 +
Past two weeks:
 +
*Preparing Annual Work Plans
 +
*Prepared for and/or attended meetings:
 +
**Division Department Heads
 +
**CASA Monthly Group
 +
**Cooler RIng
 +
**JLEIC R&D
 +
**LERF Kickoff
 +
**JLEIC Planning
 +
**OFCCP Mock Audit of Recruitment
 +
**JPOS'17
 +
**JLAAC
  
 +
Next two weeks:
 +
*Preparing Annual Work Plans
 +
*Planning vacation for 9/20 and 9/25-9/29
 +
*Preparing for and attending meetings:
 +
**Appraisal Training
 +
**JLAB S&T agenda
 +
**SBIR Discussion
 +
**FY18 Budget exercise
 +
**JLEIC R&D, Planning, Monthly Bob Update, Parameter CoordinationNo report.
  
  
 +
----
 +
'''Accelerator Physics (T. Satogata)''' <br>
 +
Todd Satogata
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - JLEIC: Continue assembling documents, pCDR meetings/planning
 +
      - JLEIC: Continued esme simulations for coasting beam instability evaluation
 +
      - ADMIN: AAC review preparations, talk (Sep 13-15)
 +
      - IPAC18: invited program followup, registration SPMS work
 +
      - OPS: BTeam (Sep 5), ATLis cleanup, documentation
 +
      - ODU: USPAS January 2018 class coordination
 +
      - ODU: JMU PHYS 417 class sharing, 4-VA inquiries
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - ADMIN: Appraisal training (Sep 19)
 +
      - OPS: BTeam (Sep 19), ATLis cleanup, troubleshooting guide, RSR accounting
 +
      - IPAC18: invited program finalization, registration opening
 +
      - JLEIC: Continue assembling documents, pCDR meetings/planning
 +
      - JLEIC: Continued esme simulations for coasting beam instability evaluation
 +
      - ODU: USPAS January 2018 class coordination (registration opening)
 +
      - ADMIN: Attend Neil Symposium (Sep 27)
 +
      - JMU seminar/trip (Sep 29)
  
 +
Alex Bogacz
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - IPAC18: APS scientific publication board org for light peer review
 +
      - JLEIC/PERLE: Talks on synergy, planning at LHeC workshop and AAC
 +
      - ADMIN: AAC review preparations, talk (Sep 13-15)
 +
      - USPAS: Continue work on lectures for "Practical Accelerator Design"
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - NUFACT: NUFACT'17, talk on "Muon Acceleration for Neutrino Factory and Beyond"
 +
      - IPAC18: Continue APS scientific publication board org for light peer review
 +
      - ADMIN: Invention disclosure review, TRC work
  
 +
David Douglas
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - VACATION: Aug 28-Sep 5
 +
      - ADMIN: Office cleaning, housekeeping, throwing away/recycling
 +
      - ADMIN: Inordinate time spent with travel; working to shorten BNL time
 +
      - ADMIN: Couple of reviews, including one PRAB review paper
 +
      - PERLE: Fire drill on PERLE motivations (Sep 11-12)
 +
      - JLEIC: Working through implications of Slava tilted solenoid concept
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - JLEIC: More work beating on tilted solenoid, comparison to DIMAD
 +
      - JLEIC: respond to any results Chris develops on the simple CCR
 +
        arcs (and write up the simple arc)
 +
      - ADMIN: Continue prep of talks for collaboration meeting and Bonn
 +
      - PERS: sedation - which I'm going to need if travel planning
 +
        doesn't settle down...
 +
      - ADMIN: Particplate/planning for Neil symposium (Sep 27)
  
 +
Rui Li
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - ADMIN: take care matters in thesis award committee (may delay
 +
        Cheng-Ying's nomination to next year to avoid conflict)
 +
      - ADMIN: listen to talks at the AAC
 +
      - JLEIC: discuss with Kirsten about her puzzle found in the ASTRA
 +
        simulation of the magnetized beam transport---possible signal
 +
        to noise problem
 +
      - JLEIC: discuss with Salvador on his studies of crab cavity HOM
 +
        coupled-bunch instability---the Rs and Q are orders of
 +
        magnitude bigger than those found in accelerating cavities,
 +
        suggested him to check similar data from existing crab cavities
 +
        to see whether others have better HOM damping
 +
      - ADMIN: get to know Eric's plan for his Fulbright application,
 +
        in preparing recommendation letter
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - JLEIC: start to work on slides summarizing my understanding of
 +
        electron cloud in JLEIC (for presentation at R&D meeting)
 +
      - JLEIC: start to work on slides summarizing JLEIC collective
 +
        effects for the upcoming collaboration meeting in BNL
 +
      - ADMIN: continue to work on matters for the thesis award
 +
        committee (deadline is 9/16)
  
 +
Ed Nissen
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - ADMIN: Attend JPos
 +
      - JLEIC: Further work on phase space painting, booster space
 +
        charge acceleration simulations.
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - JLEIC: Further work on phase space painting, booster space
 +
        charge acceleration simulations.
  
 +
Chris Tennant
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - ADMIN: FFAG Workshop: Sep 6-7 (school), Sep 8-11 (workshop)
 +
      - JLEIC: (re-)learning Bmad
 +
      - VACATION: Sep 12-15
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - JLEIC: analyze CCR arc with Bmad
 +
      - JLEIC: learn to use Bmad with CSR shielding (benchmark with
 +
        other codes)
 +
      - JLEIC: uBI gain for CCR arc (learn to use Cheng-Ying's code for
 +
        magnetized beams)
 +
      - PERLE: uBI gain for PERLE (learn to use Cheng-Ying's code
 +
        including acceleration)
  
 +
Randy Gamage
 +
    Previous two weeks (Sep 4-Sep 15)
 +
      - Dissertation writing: Continue coasting beam chapter, tech note
 +
    Next two weeks (Sep 18-Sep 29)
 +
      - Dissertation writing: Hopefully coasting beam chapter, tech note
 +
 +
 +
----
 +
'''Accelerator R and D (Y. Zhang)'''<br>
 +
<br>
 +
Fanglei Lin
 +
*Worked on studying the chromaticity compensation and dynamic aperture in the electron collider ring and presented the results in the nonlinear beam dynamics bi-weekly meeting.
 +
*Worked on the coupling compensation of detector solenoid in the electron collider ring.
 +
*Attended the JPoS17 workshop.
 +
*Miscellaneous: attended discussion of IP region design, discussion of spin tracking with Desmond Barber, attended the CASA monthly meeting.
 +
 +
 +
Vasiliy Morozov
 +
*Geometry tagging LDRD: simulations, data analysis, poster preparation.
 +
*Preparing for and participating in the Accelerator Advisory Committee meeting: presented a talk on JLEIC R&D.
 +
*Attending JPos'17.
 +
*Preparing a revised EIC R&D plan and sending it to Manouchehr.
 +
*Miscellaneous: ion polarization, crab crossing, IR design.
 +
 +
 +
Amy Sy
 +
*Simulating larger coils in second half of toroidal merger for better injection of high energy beam. Testing injection of the low energy beam through the larger coils on both original centerline and on the centerline of the large coils.
 +
*Assisting with the LDRD on geometry tagging of heavy ions by running GEMC simulations. Modifying input scripts to track particles at specific locations in the detector geometry and confirming that the code properly tracks heavy ions.
 +
*Attended the JPOS2017 workshop.
 +
 +
 +
Yuhong Zhang
 +
*Attended JLAAC meeting and gave a talk
 +
*Prepared a talk at COOL17 workshop
 +
*Continued organization of EIC Collaboration meeting
 +
*Attended JPOS2017
 +
*Updated multi-stage cooling scheme
 +
 +
 +
 +
----
 +
'''Computational Physics (Y. Roblin)'''<br>
 +
<br>
 +
Yves Roblin<br>
 +
Last 2 weeks:
 +
*JPOS17 workshop
 +
*preparing for Hall A startup (changes to procedures because of tritium target)
 +
*more simulations for JPOS17 white paper
 +
*various discussions with Kirsten
 +
   
 +
Next 2 weeks:
 +
*start preparing for coll. meeting
 +
*beam beam simulations for the main kinematics taking into
 +
*account higher order transport map
 +
 
 +
 +
Kirsten Deitrick<br>
 +
Last two weeks:
 +
*Simulation:
 +
**set up GPT on cluster
 +
**all GPT tutorials
 +
**calculating eigen emittances of simulated magnetized beam
 +
*Meetings:
 +
**GTS simulations
 +
**Alicia re: GPT
 +
Next two weeks:
 +
*reading on wakefield/impedance
 +
*meeting with Fay to hand over GPT GTS and LERF input files
 +
*possibly another meeting with Alicia for GPT
 +
*continue to get familiar with GPT
 +
*begin evaluating LERF merger designs using GPT
 +
 +
 +
River Huang
 +
*Working on developing the code needed to integrate crabbing effects into beambeam calculations. Developing an analytical model first:
 +
"With help of Vasiliy, I am studying the Beam-Beam Effects in Particle Colliders in last two weeks. Especially, I finished the calculation code (using python) of the luminosity for “head-on” simulation. The simulation results are consistent with previous research results.  Now we plan to develop the code for different cases."
 +
 +
 +
He Zhang:
 +
*Cooling simulation for JLEIC - Yuhong needs some plots about the electron cooling during collision at 40 GeV for his talk. Before only the 100 GeV case was simulated, because the higher energy makes the cooling more challenging. I simulated the 40 GeV case for proton beam during collision with 2 nC/bunch cooling electron beam and 60 m long cooler. As expected, the emittance can be maintained at about 0.3 mm*mrad and the momentum spread is maintained at about 0.8x10-3. Another simulation is the DC cooling in the booster ring with Jiquan’s new injection scheme. The purpose is to compare which is better to put the DC cooling in the booster ring at 2 GeV/u or in the collider ring at 8 GeV/u. Four different cases with electron current 2 A or 3 A and electron bunch size 2 sigma or 3 sigma of the proton beam size were simulated. In the best case with 3 A and 2 sigma electron beam, the cooling reaches equilibrium in about one minutes, and reaches 0.5 mm*mrad in about 0.75 minutes. The new injection scheme will inject 26 times. The cooling will be repeated 26 times and costs totally 19 minutes, if the cooling is put in the booster. As simulated before, DC cooling at 8 GeV/u in the collider ring cost less than 15 minutes to reach equilibrium. Considering the total time and the complication of stopping the ramping for cooling in booster, it is still preferred to have the DC cooling in the collider ring.
 +
*JSPEC development - A minor update of JSPEC has been done for lattice file loading. Before JSPEC requires the tws file from MAD X contains the TWISS parameters in a fixed order. I found it inconvenient, because the TWISS parameters are usually not saved in that order if the tws file is not specifically generated for JSPEC. The new function will detect the order in the tws file and load the respective TWISS parameters according to the tws file. This update has been pushed to github. 
 +
*Model of the electron beam space charge in cooling simulation - According to various references, the space charge effect of the electron beam could affect the electron beam in the following three aspects: increase of the transverse temperature by extra Larmor motion, dependence of the longitudinal momentum spread on transverse positions, shift of the Larmor circle in the transverse directions. I am re-deriving the formulas following the references.
 +
*Paper on heat load and trip rate optimization - Continue writing this paper and finished all plots. I think I will be able to finish it in the next week.
 +
Next two weeks work plan:
 +
*Continue developing the turn-by-turn tracking for IMP experiment
 +
*Continue developing the space charge model for cooling
 +
*Finish the optimization paper
 +
 +
 +
----
 +
'''Diagonistic Development (K. Jordan)'''<br>
 +
 +
Kevin Jordan
 +
*Worked on LCLS II CM testing in the LERF
 +
*Kickoff on the 8th, SLAC kickoff on the 14th, MCC kickoff on the 15th
 +
*Closing in on waveguide layout - that defines location of all equipment
 +
*Got initial spectrum of BNNT in the GTS
 +
<br>
 +
Joe Gubeli
 +
*Added new imager to 6E02 briefly but ran into illumination issues.
 +
*Printed a new LED plate and it tested well on a insertable assembly.
 +
*Received the parts for the one lens viewer imager. Played a little with the WaveRunner and attended an IMP meeting.
 +
*Talked to Tief about an idea for a new diagnostics in Hall D.
 +
*Seems like there was something else but can't remember.
 +
<br>
 +
Mike Tiefenback
 +
*Most of my effort the past two weeks related to JPos17 and the AAC meeting.  In addition to the two talks for JPos17, my suggestions to Spata on "special topics" resulted in a request for a presentation on CASA's operational involvement in CEBAF for the Accelerator Advisory Committee.  As an aside, I was asked for 2K anemometry references by Ed Daly, and for an analysis of 2K mass flow literature.  I don't know exactly what he wants, and have asked him, but as yet have received no reply.
 +
*In looking at the Arc 10 SLM complement that would be well-fitted for operational tuning, I recognized that the AA30 dipole installation has a horizontal dispersion of approximately 20 cm, which is not perfect, but is really pretty good for isolating energy spread from emittance and allowing envelope matching via multiple profile measurements.  Over the span (the 3/4 of the arc from AA06 through AA30) the homologous points will suffer approximately a 15% growth in beam size due to SR effects, mostly due to emittance.  I expect to start a series of computations to estimate the performance of such a system in the presence of leakage dispersion.  The 2T06 common dipole, 3-beam SLM installation still looks very interesting, both for ops and as a way to try out an optical BPM.
 +
*It still seems to me to be necessary to learn how the C-S plot data indicated so convincingly that the 2R optics error was no later than 2R02.  Coupled with this, as follow-on to the general magnet system investigations of DC Power, I have begun helping them design a probe fixture to fit into in-tunnel quadrupoles around the beam-pipe obstruction to allow for some quantitative field measurements to verify wiring integrity.
 +
*I'm still looking on the side at the relationship between the Synchrotron Radiation spectrum and the Thomas precession.  They cannot be unrelated.  From a physics standpoint, every correct treatment will result in the (same) correct answer.  However, each different treatment will exploit and illuminate different aspects of physics.  I'm interested in what the Thomas precession means in a philosophical sense: does the electron really see the world spinning madly around it as it undergoes what in the lab frame is a smooth and gentle bend?  Someone posted an arxiv article concluding that the Thomas precession is not involved in SR.  His reasoning appears flawed.  He reported w/o detail that the Thomas precession in the electron frame results in an "incorrect" spectrum, but with no details on what he did and what was incorrect.  Since using physics properly must result in the correct answer, I suspect he did not treat some details correctly.  With no description of what he did, he may have left out a modulation of the frame resulting from the electric field in the particle frame, which would smear the spectrum.  Perhaps something useful remains to be learned.  I'll comment that the first correct treatment of spin and Zeeman effect using the Dirac equation did not tell anyone about the Thomas precession.  But it was included automatically, silently, as a result of using a properly Lorentz invariant formalism.  It was simply hidden until Thomas called it out and showed how it resolved a relativistically incorrect aspect of the classical computation.
  
  

Latest revision as of 08:51, 19 September 2017

Director (M. Spata)
Past two weeks:

  • Preparing Annual Work Plans
  • Prepared for and/or attended meetings:
    • Division Department Heads
    • CASA Monthly Group
    • Cooler RIng
    • JLEIC R&D
    • LERF Kickoff
    • JLEIC Planning
    • OFCCP Mock Audit of Recruitment
    • JPOS'17
    • JLAAC

Next two weeks:

  • Preparing Annual Work Plans
  • Planning vacation for 9/20 and 9/25-9/29
  • Preparing for and attending meetings:
    • Appraisal Training
    • JLAB S&T agenda
    • SBIR Discussion
    • FY18 Budget exercise
    • JLEIC R&D, Planning, Monthly Bob Update, Parameter CoordinationNo report.


Accelerator Physics (T. Satogata)
Todd Satogata 

   Previous two weeks (Sep 4-Sep 15)
     - JLEIC: Continue assembling documents, pCDR meetings/planning
     - JLEIC: Continued esme simulations for coasting beam instability evaluation
     - ADMIN: AAC review preparations, talk (Sep 13-15)
     - IPAC18: invited program followup, registration SPMS work
     - OPS: BTeam (Sep 5), ATLis cleanup, documentation
     - ODU: USPAS January 2018 class coordination
     - ODU: JMU PHYS 417 class sharing, 4-VA inquiries
   Next two weeks (Sep 18-Sep 29)
     - ADMIN: Appraisal training (Sep 19)
     - OPS: BTeam (Sep 19), ATLis cleanup, troubleshooting guide, RSR accounting
     - IPAC18: invited program finalization, registration opening
     - JLEIC: Continue assembling documents, pCDR meetings/planning
     - JLEIC: Continued esme simulations for coasting beam instability evaluation
     - ODU: USPAS January 2018 class coordination (registration opening)
     - ADMIN: Attend Neil Symposium (Sep 27)
     - JMU seminar/trip (Sep 29)

Alex Bogacz 

   Previous two weeks (Sep 4-Sep 15)
     - IPAC18: APS scientific publication board org for light peer review
     - JLEIC/PERLE: Talks on synergy, planning at LHeC workshop and AAC
     - ADMIN: AAC review preparations, talk (Sep 13-15)
     - USPAS: Continue work on lectures for "Practical Accelerator Design"
   Next two weeks (Sep 18-Sep 29)
     - NUFACT: NUFACT'17, talk on "Muon Acceleration for Neutrino Factory and Beyond"
     - IPAC18: Continue APS scientific publication board org for light peer review
     - ADMIN: Invention disclosure review, TRC work

David Douglas 

   Previous two weeks (Sep 4-Sep 15)
     - VACATION: Aug 28-Sep 5
     - ADMIN: Office cleaning, housekeeping, throwing away/recycling
     - ADMIN: Inordinate time spent with travel; working to shorten BNL time
     - ADMIN: Couple of reviews, including one PRAB review paper
     - PERLE: Fire drill on PERLE motivations (Sep 11-12)
     - JLEIC: Working through implications of Slava tilted solenoid concept
   Next two weeks (Sep 18-Sep 29)
     - JLEIC: More work beating on tilted solenoid, comparison to DIMAD
     - JLEIC: respond to any results Chris develops on the simple CCR
       arcs (and write up the simple arc)
     - ADMIN: Continue prep of talks for collaboration meeting and Bonn
     - PERS: sedation - which I'm going to need if travel planning
       doesn't settle down...
     - ADMIN: Particplate/planning for Neil symposium (Sep 27)

Rui Li 

   Previous two weeks (Sep 4-Sep 15)
     - ADMIN: take care matters in thesis award committee (may delay
       Cheng-Ying's nomination to next year to avoid conflict)
     - ADMIN: listen to talks at the AAC
     - JLEIC: discuss with Kirsten about her puzzle found in the ASTRA
       simulation of the magnetized beam transport---possible signal
       to noise problem
     - JLEIC: discuss with Salvador on his studies of crab cavity HOM
       coupled-bunch instability---the Rs and Q are orders of
       magnitude bigger than those found in accelerating cavities,
       suggested him to check similar data from existing crab cavities
       to see whether others have better HOM damping
     - ADMIN: get to know Eric's plan for his Fulbright application,
       in preparing recommendation letter
   Next two weeks (Sep 18-Sep 29)
     - JLEIC: start to work on slides summarizing my understanding of
       electron cloud in JLEIC (for presentation at R&D meeting)
     - JLEIC: start to work on slides summarizing JLEIC collective
       effects for the upcoming collaboration meeting in BNL
     - ADMIN: continue to work on matters for the thesis award
       committee (deadline is 9/16)

Ed Nissen 

   Previous two weeks (Sep 4-Sep 15)
     - ADMIN: Attend JPos
     - JLEIC: Further work on phase space painting, booster space
       charge acceleration simulations.
   Next two weeks (Sep 18-Sep 29)
     - JLEIC: Further work on phase space painting, booster space
       charge acceleration simulations.

Chris Tennant 

   Previous two weeks (Sep 4-Sep 15)
     - ADMIN: FFAG Workshop: Sep 6-7 (school), Sep 8-11 (workshop)
     - JLEIC: (re-)learning Bmad
     - VACATION: Sep 12-15
   Next two weeks (Sep 18-Sep 29)
     - JLEIC: analyze CCR arc with Bmad
     - JLEIC: learn to use Bmad with CSR shielding (benchmark with
       other codes)
     - JLEIC: uBI gain for CCR arc (learn to use Cheng-Ying's code for
       magnetized beams)
     - PERLE: uBI gain for PERLE (learn to use Cheng-Ying's code
       including acceleration)

Randy Gamage 

   Previous two weeks (Sep 4-Sep 15)
     - Dissertation writing: Continue coasting beam chapter, tech note
   Next two weeks (Sep 18-Sep 29)
     - Dissertation writing: Hopefully coasting beam chapter, tech note


Accelerator R and D (Y. Zhang)

Fanglei Lin

  • Worked on studying the chromaticity compensation and dynamic aperture in the electron collider ring and presented the results in the nonlinear beam dynamics bi-weekly meeting.
  • Worked on the coupling compensation of detector solenoid in the electron collider ring.
  • Attended the JPoS17 workshop.
  • Miscellaneous: attended discussion of IP region design, discussion of spin tracking with Desmond Barber, attended the CASA monthly meeting.


Vasiliy Morozov

  • Geometry tagging LDRD: simulations, data analysis, poster preparation.
  • Preparing for and participating in the Accelerator Advisory Committee meeting: presented a talk on JLEIC R&D.
  • Attending JPos'17.
  • Preparing a revised EIC R&D plan and sending it to Manouchehr.
  • Miscellaneous: ion polarization, crab crossing, IR design.


Amy Sy

  • Simulating larger coils in second half of toroidal merger for better injection of high energy beam. Testing injection of the low energy beam through the larger coils on both original centerline and on the centerline of the large coils.
  • Assisting with the LDRD on geometry tagging of heavy ions by running GEMC simulations. Modifying input scripts to track particles at specific locations in the detector geometry and confirming that the code properly tracks heavy ions.
  • Attended the JPOS2017 workshop.


Yuhong Zhang

  • Attended JLAAC meeting and gave a talk
  • Prepared a talk at COOL17 workshop
  • Continued organization of EIC Collaboration meeting
  • Attended JPOS2017
  • Updated multi-stage cooling scheme


Computational Physics (Y. Roblin)

Yves Roblin
Last 2 weeks:

  • JPOS17 workshop
  • preparing for Hall A startup (changes to procedures because of tritium target)
  • more simulations for JPOS17 white paper
  • various discussions with Kirsten

Next 2 weeks:

  • start preparing for coll. meeting
  • beam beam simulations for the main kinematics taking into
  • account higher order transport map


Kirsten Deitrick
Last two weeks:

  • Simulation:
    • set up GPT on cluster
    • all GPT tutorials
    • calculating eigen emittances of simulated magnetized beam
  • Meetings:
    • GTS simulations
    • Alicia re: GPT

Next two weeks:

  • reading on wakefield/impedance
  • meeting with Fay to hand over GPT GTS and LERF input files
  • possibly another meeting with Alicia for GPT
  • continue to get familiar with GPT
  • begin evaluating LERF merger designs using GPT


River Huang

  • Working on developing the code needed to integrate crabbing effects into beambeam calculations. Developing an analytical model first:

"With help of Vasiliy, I am studying the Beam-Beam Effects in Particle Colliders in last two weeks. Especially, I finished the calculation code (using python) of the luminosity for “head-on” simulation. The simulation results are consistent with previous research results. Now we plan to develop the code for different cases."


He Zhang:

  • Cooling simulation for JLEIC - Yuhong needs some plots about the electron cooling during collision at 40 GeV for his talk. Before only the 100 GeV case was simulated, because the higher energy makes the cooling more challenging. I simulated the 40 GeV case for proton beam during collision with 2 nC/bunch cooling electron beam and 60 m long cooler. As expected, the emittance can be maintained at about 0.3 mm*mrad and the momentum spread is maintained at about 0.8x10-3. Another simulation is the DC cooling in the booster ring with Jiquan’s new injection scheme. The purpose is to compare which is better to put the DC cooling in the booster ring at 2 GeV/u or in the collider ring at 8 GeV/u. Four different cases with electron current 2 A or 3 A and electron bunch size 2 sigma or 3 sigma of the proton beam size were simulated. In the best case with 3 A and 2 sigma electron beam, the cooling reaches equilibrium in about one minutes, and reaches 0.5 mm*mrad in about 0.75 minutes. The new injection scheme will inject 26 times. The cooling will be repeated 26 times and costs totally 19 minutes, if the cooling is put in the booster. As simulated before, DC cooling at 8 GeV/u in the collider ring cost less than 15 minutes to reach equilibrium. Considering the total time and the complication of stopping the ramping for cooling in booster, it is still preferred to have the DC cooling in the collider ring.
  • JSPEC development - A minor update of JSPEC has been done for lattice file loading. Before JSPEC requires the tws file from MAD X contains the TWISS parameters in a fixed order. I found it inconvenient, because the TWISS parameters are usually not saved in that order if the tws file is not specifically generated for JSPEC. The new function will detect the order in the tws file and load the respective TWISS parameters according to the tws file. This update has been pushed to github.
  • Model of the electron beam space charge in cooling simulation - According to various references, the space charge effect of the electron beam could affect the electron beam in the following three aspects: increase of the transverse temperature by extra Larmor motion, dependence of the longitudinal momentum spread on transverse positions, shift of the Larmor circle in the transverse directions. I am re-deriving the formulas following the references.
  • Paper on heat load and trip rate optimization - Continue writing this paper and finished all plots. I think I will be able to finish it in the next week.

Next two weeks work plan:

  • Continue developing the turn-by-turn tracking for IMP experiment
  • Continue developing the space charge model for cooling
  • Finish the optimization paper


Diagonistic Development (K. Jordan)

Kevin Jordan

  • Worked on LCLS II CM testing in the LERF
  • Kickoff on the 8th, SLAC kickoff on the 14th, MCC kickoff on the 15th
  • Closing in on waveguide layout - that defines location of all equipment
  • Got initial spectrum of BNNT in the GTS


Joe Gubeli

  • Added new imager to 6E02 briefly but ran into illumination issues.
  • Printed a new LED plate and it tested well on a insertable assembly.
  • Received the parts for the one lens viewer imager. Played a little with the WaveRunner and attended an IMP meeting.
  • Talked to Tief about an idea for a new diagnostics in Hall D.
  • Seems like there was something else but can't remember.


Mike Tiefenback

  • Most of my effort the past two weeks related to JPos17 and the AAC meeting. In addition to the two talks for JPos17, my suggestions to Spata on "special topics" resulted in a request for a presentation on CASA's operational involvement in CEBAF for the Accelerator Advisory Committee. As an aside, I was asked for 2K anemometry references by Ed Daly, and for an analysis of 2K mass flow literature. I don't know exactly what he wants, and have asked him, but as yet have received no reply.
  • In looking at the Arc 10 SLM complement that would be well-fitted for operational tuning, I recognized that the AA30 dipole installation has a horizontal dispersion of approximately 20 cm, which is not perfect, but is really pretty good for isolating energy spread from emittance and allowing envelope matching via multiple profile measurements. Over the span (the 3/4 of the arc from AA06 through AA30) the homologous points will suffer approximately a 15% growth in beam size due to SR effects, mostly due to emittance. I expect to start a series of computations to estimate the performance of such a system in the presence of leakage dispersion. The 2T06 common dipole, 3-beam SLM installation still looks very interesting, both for ops and as a way to try out an optical BPM.
  • It still seems to me to be necessary to learn how the C-S plot data indicated so convincingly that the 2R optics error was no later than 2R02. Coupled with this, as follow-on to the general magnet system investigations of DC Power, I have begun helping them design a probe fixture to fit into in-tunnel quadrupoles around the beam-pipe obstruction to allow for some quantitative field measurements to verify wiring integrity.
  • I'm still looking on the side at the relationship between the Synchrotron Radiation spectrum and the Thomas precession. They cannot be unrelated. From a physics standpoint, every correct treatment will result in the (same) correct answer. However, each different treatment will exploit and illuminate different aspects of physics. I'm interested in what the Thomas precession means in a philosophical sense: does the electron really see the world spinning madly around it as it undergoes what in the lab frame is a smooth and gentle bend? Someone posted an arxiv article concluding that the Thomas precession is not involved in SR. His reasoning appears flawed. He reported w/o detail that the Thomas precession in the electron frame results in an "incorrect" spectrum, but with no details on what he did and what was incorrect. Since using physics properly must result in the correct answer, I suspect he did not treat some details correctly. With no description of what he did, he may have left out a modulation of the frame resulting from the electric field in the particle frame, which would smear the spectrum. Perhaps something useful remains to be learned. I'll comment that the first correct treatment of spin and Zeeman effect using the Dirac equation did not tell anyone about the Thomas precession. But it was included automatically, silently, as a result of using a properly Lorentz invariant formalism. It was simply hidden until Thomas called it out and showed how it resolved a relativistically incorrect aspect of the classical computation.


LERF (S. Benson)

September 5-15

  • Prepared talks for JPos17, COOL17, and EIC collaboration meeting
  • Attended JPos17 and organized LERF tour
  • Continued to clean up the materials moved from the trailers to the LERF
  • Discussed possible proposal for positron source at the LERF
  • Worked on possible CRADA for high efficiency FEL development
  • Debriefed with CI officers about the CRADA

September 18-29

  • Attend COOL17 and present talk on bunched beam cooler
  • Attend Neil Symposium and host the speakers
  • Complete detailed statement of work for CRADA
  • Writeup JPos publication
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